Ch 4.2 & 4.3 Slope-Intercept Method Objective: To identify the slope and y-intercept and graph using the Slope-Intercept Method.

3 Methods of Graphing Table (T-Chart) Intercepts Slope-Intercept x y

where the line crosses y-axis Definitions Slope-Intercept Form: y = mx + b Slope (m): rise/run as a fraction y-Intercept (b): where the line crosses y-axis

Draw a line through the two points Rules 1) Use the y-intercept (b) to plot the first point (0, b) 1) Use slope (m) to “count” rise/run from the y-intercept to plot the second point rise/run from (0, b) Draw a line through the two points

Identify the slope (rise/run) as a fraction and the y-intercept. 1) y = x - 4 5 -2 2) y = x - 1 8 9 4 -1 5 -2 -4 = b m = m = = b 8 9 4 4) y = -2x - 1 3) y = 3x + 4 3 -2 -1 = b m = 4 = b m = 1 1 5) y = 5x + 0 6) y = 0x + 6 5 m = 0 = b m = 6 = b 1 1

Example 1 y +3 +2 +3 +2 x Plot the y-intercept rise +2 (up) run +3 (right) +3 +2 +3 +2 x

Example 2 -1 or y -2 +1 +2 x rise -1 (down) run +2 (right) rise +1 (up) x run -2 (left)

Example 3 y = 2x + 3 y +1 rise +2 (up) +2 run +1 (right) x

Example 4 -3 or y -2 x +3 +2 rise -3 (down) run +2 (right) rise +3 (up) x run -2 (left) +3 -3 +2

Classwork Graph each equation 1) 2)

3) 4)

5) 6)